Ryan Lochte was in a class of his own as he lowered his own world record in the 200 metres individual medley at the World Short-Course Championships in Istanbul.
The 11-time Olympic medallist already held a clear lead after the opening butterfly leg, his pace too hot to handle for what was a world-class field which included Laszlo Cseh, owner of four Olympic medals.
The American was under world-record pace from start to finish and his time of one minute 49.63 seconds took 0.45secs off his own time from 2010.
The 28-year-old destroyed his opponents, his winning margin over Daiya Seto a huge 3.17secs with Cseh a further 0.09secs behind.
Lochte said: "This is definitely a good way to end 2012.
"I was not expecting a world record - I just went in to race the hardest I can.
"This is going to be a great ending to the year, it is going to boost my confidence going into 2013."
The Florida Gator is hugely popular and was mobbed as he attempted to make his way to a press conference.
He said: "The fans are awesome - I owe them everything."
Daniel Gyurta added the short-course title to Olympic gold in the 200m breaststroke with Great Britain's Michael Jamieson second as the pair repeated their one-two at the Aquatics Centre in the summer.
The Hungarian had hoped to have lowered his own world record coming into the competition but had to be content with a championship record of 2:01.35.
His fellow Hungarian Katinka Hosszu set a championship record of 58.49 in the women's 100m individual medley
Britta Steffen of Germany won the 100m freestyle (52.31), Melanie Costa Schmid claimed the 400m freestyle title in 4:01.18 with just 0.06secs separating the top three, Daryna Zevina won the 200m backstroke (2:02.24) and China's Lu Ying took the 50m butterfly (25.14).
There was further success for Germany in the men's 400m freestyle as Paul Biedermann won in 3:39.15.
Vladimir Morozov has showcased his fearsome sprinting this week and tonight the 20-year-old Russian won the 50m freestyle in 20.55 ahead of Olympic champion Florent Manaudou.